Motor Connection - Danfoss VLT AutomationDrive FC 300 Design Manual

FC 300 Design Guide
Mains connection B1 and B2 (IP 21/NEMA
Type 1 and IP 55/66/ NEMA Type 12) enclo-
sures
Usually the power cables for mains are unshielded cables.

6.3.3. Motor Connection

See section General Specifications for correct
dimensioning of motor cable cross-section
and length.
Screening of cables:
twisted screen ends (pigtails). They spoil the
screening effect at higher frequencies. If it is
necessary to break the screen to install a mo-
tor isolator or motor contactor, the screen
must be continued at the lowest possible HF
impedance.
Connect the motor cable screen to both the
decoupling plate of the FC 300 and to the
metal housing of the motor.
Make the screen connections with the largest
possible surface area (cable clamp). This is
done by using the supplied installation devices
in the FC 300.
If it is necessary to split the screen to install a
motor isolator or motor relay, the screen must
be continued with the lowest possible HF im-
pedance.
NB!
Motor cable must be screened/armoured. If an unscreened/unarmoured cable is
used, some EMC requirements are not complied with. Use a screened/armoured
motor cable to comply with EMC emission specifications. For more information, see
EMC Test Results
.
Avoid installation with
MG.33.B9.02 - VLT ® is a registered Danfoss trademark
Mains connection C1 and C2 (IP 21/ NEMA
Type 1 and IP 55/66/ NEMA Type 12) enclo-
sures
Cable-length and cross-section:
quency converter has been tested with a given
length of cable and a given cross-section of
that cable. If the cross-section is increased,
the cable capacitance - and thus the leakage
current - may increase, and the cable length
must be reduced correspondingly. Keep the
motor cable as short as possible to reduce the
noise level and leakage currents.
Switching frequency: When frequency
converters are used together with Sine-wave
filters to reduce the acoustic noise from a mo-
tor, the switching frequency must be set ac-
cording to the Sine-wave filter instruction in
Par. 14-01.
6. How to Install
6
The fre-
103